The ZTE Open will cost $90 with a prepaid subscription

TelefA3nica will be the first to offer a commercial smartphone based on Firefox OS. The Spanish operator will start selling the ZTE Open on Tuesday for a!69 (US$90) with a prepaid subscription.

Firefox OS is built around applications written using HTML5. It is being pitched as a better alternative for low-end smartphones, and will compete head-to-head with cheap Android phones and others such as Nokia's Asha platform.

The Open, announced in February at Mobile World Congress, has a 3.5-inch screen and is powered by a 1GHz processor from Qualcomm. The smartphone also has a 3.2-megapixel camera and support for Wi-Fi and A-GPS. There is 512MB of integrated storage and 256MB of RAM, ZTE said the launch event.

The Alcatel One Touch Fire, which has the same basic specs, will also go on sale soon.

On the software side, Firefox OS integrates Facebook and Twitter, Nokia's HERE Maps -- with features such as offline access -- and, of course, the Firefox browser, according to Mozilla. The organization also pitches the platform's search features: by swiping to the right users can search for their favorite music artist and get results to buy songs, concert tickets or start listening to songs instantly, Mozilla said.

That TelefA3nica is the first to offer smartphones based Firefox OS shouldn't come as surprise. The operator has been the platform's staunchest supporter, and helped create and distribute two phones for developers, the Peak and Keon, earlier this year. The Open is the first of a number of Firefox OS devices that will be launched by TelefA3nica this year, the operator said. TelefA3nica expects LG Electronics, Huawei Technologies and Sony will also offer smartphones based on the platform.

For a!69, Spanish users will get the device as well as a a!30 balance and a 4GB microSD card. TelefA3nica will also offer Firefox OS phones in Colombia and Venezuela, it said.

Firefox OS devices have to be able to compete with Android on price, said Geoff Blaber, analyst at CCS Insight.

"[The a!69 price] is probably more competitive that I had anticipated, and it is a strong statement of intent. But the challenge is that Android is well below that price point," he said.

Deutsche Telekom isn't announcing any details on its Firefox OS launch, but the operator is planning to host an event in Poland on July 11 where it will provide more details, a spokesperson said via email. Norwegian operator Telenor will launch its first Firefox OS phones in Central and Eastern Europe this year, according to Mozilla.

To succeed Firefox OS needs strong backing from mobile operators.

"We are seeing that from TelefA3nica and Deutsche Telekom, but the question is if we are going to see other carriers embrace the platform at a strategic level," Blaber said.

Mozilla also has to convince users that betting on an unproven platform is a step worth taking, and part of that is both the quantity and quality of apps, he said. It has to show HTML5 can deliver the richness today's smartphone buyers expect, and for the vast majority of apps Blaber suspects it can, he said.

But for that to happen Mozilla will have to attract developers. A recent survey conducted by IDC and cross-platform tool vendor Appcelerator suggests that the platform is off to a good start. About 25 percent of the respondents said they were very interested in Mozilla's platform, compared to 19 percent for Ubuntu and only 9 percent for Tizen, two smartphone OSes that will start competing with Firefox OS later this year.

However, that is still a long way behind Apple's iOS and Google's Android. About 87 percent of respondents said they were very interested in iOS and 78 percent showed the same level of interest for Android, so Mozilla and the other backers of Firefox OS still have a lot of work to do.